Refinement of Isoflurane Anesthesia Scavenging  Method by Using Modified Prototypes and Personnel  Monitoring Exposure Assessment in Vivarium

Shakthi Devan R K; Yogisha  Mallikarjuna; Manivannan  Arumugam; Usha Nanjappa; Yogesha Manjegowda; Venugopal R

doi:10.48165/jlas.2024.7.1.4

Authors

Shakthi Devan R K Syngene International Limited, Bangalore, India Author
Yogisha Mallikarjuna Syngene International Limited, Bangalore, India Author
Manivannan Arumugam Syngene International Limited, Bangalore, India Author
Usha Nanjappa Biocon Bristol-Myers Squibb R&D Center, Bangalore , India Author
Yogesha Manjegowda Biocon Bristol-Myers Squibb R&D Center, Bangalore , India Author
Venugopal R Biocon Bristol-Myers Squibb R&D Center, Bangalore , India Author

DOI:

https://doi.org/10.48165/jlas.2024.7.1.4

Keywords:

Isoflurane anesthesia, Laboratory Animals, Waste anesthetic gas, Scavenging Methods, Occupational Health and Safety, Exposure Assessment

Abstract

Anesthesia is an important procedure performed in laboratory animals as part of the experimental activity. A calibrated vaporizer is recommended for precision delivery and efficient scavenging is an integral part of avoiding possible health hazards for personnel involved in gas anesthesia. The vivarium facility is equipped with scavenging devices such as activated charcoal canisters, spot extractors, fume hoods, and biosafety cabinets those are engineering controls used during isoflurane anesthesia. A modified prototype was necessitated especially when rodent procedures were conducted on the table due to a higher turnover in a barrier-maintained facility. Hence, a well-designed prototype with different shapes was developed to improve the scavenging methods during long-term tabletop anesthesia procedures where numerous animals are handled to complete the activities within the timeframe. The concentration of waste anesthetic gas was captured systematically from 13 laboratory personnel at different intervals and analyzed for quantitative exposure assessment for isoflurane. The results revealed that the waste anesthetic concentration captured for laboratory personnel was between 0.08 to 1.45 ppm. This result is below the reported recommended laboratory concentration (0.23 - 3.40 ppm). Moreover, the Time Weighted Average (TWA) personal exposure to isoflurane was found to be below the Health and Safety Executive (HSE) established Workplace Exposure Limit (WEL)-TWA (8 hours) of 50 ppm. The National Institute for Occupational Safety and Health (NIOSH) has a non-regulatory recommended exposure limit (REL) for halogenated agents (e.g., isoflurane) of 2 ppm or 15 mg/m3 as a ceiling limit (over a sampling period not to exceed one hour) during anesthetic administration. The Occupational Safety and Health Administration (OSHA) has not established a regulatory permissible exposure limit (PEL) for anesthetic gases; therefore, 2 ppm is used as the exposure threshold. Since each laboratory research and environmental conditions vary, it is important that exposure monitoring is performed at least one time to ensure isoflurane levels are less than 2 ppm. Overall, the implementation of a newly developed prototype along with canisters and an intensive exposure assessment was found to efficiently capture the waste anesthetic gas from induction chambers and surgical areas with nose cone where isoflurane is constantly delivered during anesthesia. The portable setup with active suction arms and flexible hose connectors can be placed on a table and/or enclosure to reduce the occupational exposure of Isoflurane to laboratory personnel and demonstrated that the prototype had improved the scavenging practices in the vivarium.

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